Once upon a time, a Democrat ran for mayor of New York and built his campaign around the central theme of two cities. In one city, his stump speech went, citizens were affluent and comfortable, and had all the resources of the country's largest metropolis at their disposal. For the other city, day-to-day life was an increasingly expensive, harrowing struggle. Working-class people were putting in longer hours, facing a skyrocketing cost of living, and having to make do with less. All this happened because the city had suffered a great catastrophe, and when it emerged, the fruits of the recovery went almost exclusively to the wealthy.

A number of forces have combined to make this de Blasio's moment. Peter Beinart, in a perceptive Daily Beast article, claimed de Blasio's primary victory represents the political coming-of-age of liberal millennials. But whether or not you think this is a generational changing of the guard, it's not hard to figure out why de Blasio and Ferrer have talked a similar game, but gotten back very different returns on their investments.

The first reason for de Blasio's success is that unlike Ferrer, he is running in a post-Great Recession environment. Intuitively, one would assume that the worst financial collapse since the 1930s has done widespread, indiscriminate damage to the economy. All around the country, but especially in New York, this is plainly not the case. Nationwide, the top 1% of the population earns over 20% of the income, putting Americans at levels of income inequality not seen since the Gilded Age.

De Blasio has played this situation masterfully to his advantage. He has updated Ferrer's "Two New Yorks" rhetoric for the present day, and has used it to frame everything from his plans for affordable housing to his proposal to fund universal pre-K by taxing the rich. When Ferrer ran for mayor in 2005, he crafted his "Two New Yorks" theme largely as a response to the two major setbacks that befell New York in the early part of the decade: the September 11 attacks, and the recession that followed.

But the truth is that the two downturns had little in common. The post-9/11 recession was cyclical, though its effect was magnified by the attack on the World Trade Center. The Great Recession was a systemic crisis that caused many people to rethink the entire economic order they were living under. Call de Blasio's rhetoric class warfare if you like, but after a crisis that clearly owes much to the excesses of the modern financial system, Bloomberg only doubled down in his defense of Wall Street, insisting that leaving the industry untouched would bring prosperity to the entire city. Most New Yorkers, it's safe to say, did not share the mayor's warm feelings.

Which brings us to another, more NYC-specific reason de Blasio looks poised to succeed where Ferrer didn't: De Blasio is able to capitalize on Bloomberg fatigue in a way that Ferrer never was. If the adage about presidents is that every second term since FDR's has been a disaster, the corollary for New York mayors is that third terms never, ever go well. And starting with the day Bloomberg carved out a special exemption to the city's term-limits law for himself, it seemed that the mayor's final term carried the logic of Bloombergism out to its furthest possible extent.

This isn't to say that a de Blasio victory should be seen as a wholesale rejection of the Bloomberg agenda. Exit polling from the September 10 primary pointed to a different conclusion: Most New Yorkers appreciate much of what Bloomberg has done for the city, but are simply ready to go a different route. The current mayor is nothing if not unapologetic about his governing style, and this makes him prone to excess. It's largely this, combined with the ravages of the Great Recession and (let's be honest) de Blasio's telegenic, interracial family, that will catapult the current Democratic nominee to victory on November 5.

Ferrer was onto something with his message — but it's only now that the city as a whole is catching on.